This invention generally relates to intravascular procedures, such as percutaneous transluminal coronary angioplasty (PTCA), and particularly to the exchange of guidewires during such procedures.
In classic PTCA procedures, a guiding catheter having a preshaped distal tip is percutaneously introduced into the cardiovascular system of a patient and advanced therein until the preshaped distal tip thereof is disposed within the aorta adjacent the ostium of the desired coronary artery. The guiding catheter is twisted or torqued from its proximal end, which extends outside of the patient, to turn the distal tip of the guiding catheter so that it can be guided into the coronary ostium and seated therein. A dilatation catheter having a dilatation balloon on the distal end thereof and a guidewire slidably disposed within an inner lumen of the dilatation catheter are introduced into and advanced through the proximal end of the guiding catheter to the distal tip of the guiding catheter seated within the coronary ostium. The distal tip of the guidewire is usually manually shaped (curved) by the physician or one of the attendants before it is introduced into the guiding catheter along with the dilatation catheter.
The shaped distal tip of the guidewire is first advanced out the distal tip of the guiding catheter into the patient's coronary artery. A torque is applied to the proximal end of the guidewire, which extends out of the proximal end of the guiding catheter as it is advanced within the coronary anatomy, to guide the curved or otherwise shaped distal end of the guidewire into a branch artery targeted for dilatation. The advancement of the guidewire within the target artery continues until it crosses the lesion to be dilated.
The dilatation catheter is then advanced out of the distal tip of the guiding catheter, over the previously advanced guidewire, until the balloon on the distal extremity of the dilatation catheter is properly positioned across the lesion to be dilated. Once properly positioned across the lesion, the flexible, relatively inelastic dilatation balloon on the catheter is inflated to a predetermined size with radiopaque liquid at relatively high pressures (e.g.,generally 4-12 atmospheres) to dilate the stenosed region of the diseased artery. One or more inflations of the balloon may be required to complete the dilatation of the stenosis. After the last dilatation, the balloon is deflated so that the dilatation catheter can be removed from the dilated stenosis and so that blood flow can resume through the dilated artery.
Further details of guiding catheters, dilatation catheters, guidewires, and the like for angioplasty procedures can be found in U.S. Pat. No. 4,323,071 (Simpson-Robert); U.S. Pat. No. 4,439,185 (Lundquist); U.S. Pat. No. 4,468,224 (Enzmann et al. ); U.S. Pat. No. 4,516,972 (Samson); U.S. Pat. No. 4,438,622 (Samson et al.); U.S. Pat. No. 4,554,929 (Samson et al.); U.S. Pat. No. 4,582,185 (Samson); U.S. Pat. No. 4,616,652 (Simpson); U.S. Pat. No. 4,638,805 (Powell); U.S. Pat. No. 4,748,986 (Morrison et al.); U.S. Pat. No. 4,898,577 (Badger et al.); U.S. Pat. No. 4,748,982 (Horzewski et al.); and U.S. Pat. No. 4,821,722 (Miller et al.) which are hereby incorporated herein in their entirety by reference thereto.
The assignee of the present invention, Advanced Cardiovascular Systems, Inc., markets an improved dilatation catheter under the trademark ACS RX.RTM. Coronary Dilation Catheter which is described and claimed in U.S. Pat. No. 5,040,548 (Yock), U.S. Pat. No. 5,061,273 (Yock) and U.S. Pat. No. 4,748,982 (Horzewski et al.). This dilatation catheter has a short guidewire receiving sleeve or inner lumen extending through the distal portion of the catheter. The sleeve extends proximally a distance of at least 10 cm and usually not more than about 50 cm from a first guidewire port in the distal end of the catheter to a second guidewire port in the catheter spaced proximally from the inflatable balloon of the catheter. A slit is preferably provided in the catheter wall which extends distally from the second guidewire port, preferably to a location proximal to the proximal end of the inflatable balloon to aid in the removal of the catheter from a guidewire. The structure of the catheter allows for the rapid exchange of the catheter without the need for the use of an exchange wire or adding a guidewire extension to the proximal end of the guidewire. The design of this catheter has been widely praised by the medical profession and has met with much commercial success in the market place because of its unique design.
A substantial improvement in the rapid exchange type dilatation catheters, such as described above, has recently been made by McInnes et al. which is described in copending applications Ser. No. 07/476,056, filed Feb. 7, 1990 now abandoned and Ser. No. 07/541,264 filed Jun. 19, 1990, now abandoned both entitled READILY EXCHANGEABLE PERFUSION DILATATION CATHETER, which are incorporated herein by reference. In these readily exchangeable dilatation catheters, perfusion ports are provided in the catheter shaft proximal and distal to the balloon which are in fluid communication with the guidewire receiving inner lumen to allow blood to perfuse distal to the catheter when the balloon was inflated.
However, one inconvenience with the above described dilatation catheter systems adapted for rapid exchangeability has been the inability to remove a guidewire already in place within a patient's vasculature without losing access to the vascular location. There has been no convenient way in which a replacement guidewire might be advanced through the vasculature and into the short guidewire receiving inner lumen in the distal extremity of the dilatation catheter. The in-place guidewire may need to be replaced with another guidewire having a different structure, e.g. from a floppy-type design with a separate shaping ribbon to an intermediate or standard with a core wire which extends to the distal tip of the guidewire, or it may need to be withdrawn in order to reshape the distal tip and then be reinserted. In both instances the guidewire is referred to herein as the replacement guidewire.
What has been needed and heretofore unavailable is a intraluminal catheter system which provides for the easy and rapid exchange of both the catheter or the guidewire used to guide the catheter through a body lumen or both. The present invention satisfies these and other needs.